This is a basic sauce that you can either change the herbs or the broth you want to use. It works great with the pasta water and a little shoyu as well.
Escabeche sauce is a great way to make an easy dressing for baked veggies and it preserves them very well, so you can even place the baked vegetables inside a jar and pasteurize it for a travelling meal.
Escabeche is not so acidic like a vinagrete sauce but keeps this sweet and sour mix and allows the use of citrus and fresh herbs.
Just crush and saute the garlic with salt, the red pepper powder and the onions, at the same time baking the veggies in finger sized chunks for 15 to 20 minutes
On a pan you can make the bouillon or herbal broth and once filtered you can add the corn starch and the sauteed onions.
Simmer 3 t-5 minutes.
Chop and add the parsley and vinegar. Serve on top of the baked veggies and once cold, you can keep it for one week.
Another gourmet version is called "escabechado", which is made with veggie tempura. Simply delicious

2 cloves of garlic
A pinch of sea salt
Half medium sized onion thinly chopped
2 tbsp olive oil
2 tbsp of cider vinegar
1/2 litre vegetable broth
2 tbsp corn starch
1 tbsp chopped parsley
Pepper powder to taste (spanish people typically add 1/2 tbsp)